I just can’t find a decent email client that looks like it’s from the last 20 years. Geary and Evolution both appear to be pretty modern but something about using Gmail with a Yubikey just doesn’t work and neither of them will connect to my account. Both on Fedora and OpenSUSE. Thunderbird works but it’s so old fashioned and Betterbird doesn’t look much better. What’s everyone else using?
If you need less information on screen, they invented a great thing for that in the 90s: resizable windows. And later, HiDPI-aware interface scaling.
That is the right way to control information density. The user can control both of these however they like and set it to whatever they work best with, and it applies across the system. You can’t do that with usually custom written interfaces that insist on putting like two lines of text worth of whitespace between every UI element.